Landfill sites that earn carbon offsets for capturing excess gas emitted from rotting waste will face stricter regulations under a new proposal designed to improve the integrity of the federal government’s carbon credits scheme.

The credits, which are earned by companies that burn the methane emitted by garbage waste to produce electricity, account for around a quarter of offsets purchased under the government’s safeguard mechanism, a policy designed to reduce carbon pollution by some of Australia’s top-emitting facilities.